Nope it's really stupid. Just a charge pump. Not sure how it gets the sender to slow down. I'd like to do the same thing only smarter. We know signals travel at less than the speed of light. I have verified that it's only going about 30KB/sec. That's what gave me this idea in the first place! Ideas? How does it do it without any additional hardware? Magic?

1) Blindly and stupidly repeat the USB data both ways using the Host Shield library. There will be no Xbee involved at first. I realize this will not work for most applications or hardware, because of the huge delay and slow data rate. But isn't that what my CAT5 cable is doing so well at 300m? It totally screws up the timing and the data rate, yet it works perfectly. One step at a time, first I will try it at the full shield speed, with little delay or cable length. At the best data rate. One byte in, one byte out, in both directions. Will that work?

Then comes the problems. The difficulty in my case is how to tell the sender to pause or slow down, in both directions. Otherwise I will lose data. How does the CAT5 cable do that? Ideas?

2) Use the PTP library v2.0 to get the thumbnail object from the Canon DSLR. Send it to the PC using USB. View the data using the terminal to make sure it appears to match the image file on the camera. In the next version I will figure out how to send it wirelessly. The problem with 2) is that it will never be compatible with the existing EOS utility provided by Canon which might work in 1).

Great price for what it does! Your second link sounds too good to be true for $50 on Amazon. It would go inside, or just outside of the house. Powered by 110vac. I like the price compared to others. Maybe at some shorter distance I can use it to talk to Eyefi directly. What's the catch? Maybe it's a misunderstanding. Maybe it's just the antenna?

In my case, there would be no way to trigger the shutter.

Did you mean for me to use them together? Ah the plus sign. The first link requires a cat5 CABLE like mine. That cannot be plugged into a wireless router or your second link. I wish. Went back to read it again. I'm wrong! Thinking...

All I need is a cheap router and your first link in the woods. Not much power! Great idea! Only $100 for both!

Can you find a wireless router that has a sleep mode? How would it know when to wake up? The Uno could do this every 5 minutes!

You should use the USB over ip hub with a cheap n router out in the woods. Put Linux on the router and you may be able to power the radios on/off. Also , if it has GPIOs you could use those for the shutter. Otherwise, connect an arduino + Ethernet shield to the router for shutter control.

And they said it couldn't be done for less than $100 just a few short days ago above!

Linux on the router? GPIO? Example please. I wouldn't need to trigger the shutter if the EOS utility was working over USB. I would need to trigger it if I was using Eyefi. I'd only like to refine this idea by allowing the router to sleep to save power.

You should probably be aware the the maximum usable range of 802.11b/g/n is in the range of ~90m, with no obstructions--getting it to 300m would require directional antennas and suchlike.

What was said to be impossible was to make a 300m transmitter/receiver for $100. You still haven't (and probably never will) accomplish this goal, but your current trend of accepting more realistic approximates is much more likely to succeed.

You would put linux on a dd-wrt compatible router, which would give you access to the hardware. You'd then need to program it to toggle the GPIO (general purpose input/output) pins available on the board. The Linksys WRT54GL is the traditional router used for this, but it's not going to come close to a 300m range. Shop around for something more likely to work.

All true! Awhile back I revised my $100 budget to include outdoor things I don't already own. So I'm excluding the directional antenna in his 2nd link which can also be used for other projects. My concern was the value outside which could be damaged or stolen. This is currently less than $100 as suggested above. My 300m requirement is not written in stone. I'd like to come close to reaching it ideally.